Sync between xdj-xz and djs-1000 don't work

Hi have read the user manual page 21.

The sync of xdj-xz works perfect. 

I bought a djs-1000. unfortunately the sync don't work. 

I connected a pro dj link lan cabel, defined the sync in the settings to pro dj - link but the sync don't work.

on djs-1000 always light the master light .... but it isn't the master and light on the same time with the master on xdj-xz .... what's wrong ?

Thanks for helping me. Urs